Mistaken Identity (2)

Melanie Monkton drifts back into the story and out of it again — she spent the weekend in London with a jockey her mother was also sleeping with, and her father was faking the euthanisation of her horse to defraud his insurers — a domestic farce that keeps the episode's plates spinning while the real case hardens. Mike Patterson is cleared: he is a liar and an adulterer, but not a killer. The drowned man is named as Reginald Molloy, and the connection Frost has been circling snaps into focus.

Thirteen years earlier, Molloy's mother and Paul Harris's father were both witnesses at the trial of Charlie Layman, a brutal thug convicted of a fatal armed robbery. Layman died in prison a year ago — but the pattern continues: every witness from that trial has lost a relative in the past year, each death made to look natural or accidental. The killer is not Layman. It is his son, Jeffrey Meadows — taken into care as a boy to shield him from an abusive father, but never freed from him: Layman kept sending letters from prison, controlling his son to the end. Meadows has been working his way through the witnesses' families, making them suffer the way he suffered, and Pam Hartley is his last target — she was the psychologist who recommended he be taken into care.

Meadows abducts Pam and wedges her into the pipework of an auxiliary pumping house, then starts to flood it. Frost and Lonnegan track him down, but with his work complete, Jeffrey leaps from a bridge to his death. Mullett, of all people, works out where Pam is being held, and Frost reaches her just before she drowns; the HMIC inspector, nursing a vendetta against Frost's unorthodox methods, moves to withhold the station's funding — and Frost and Mullett, for once on the same side, persuade him that the crimes they have just solved prove Denton's worth.

Mistaken Identity (2), written by David Gilman and directed by Roger Bamford, closes the two-parter with the series' darkest psychology yet — a killer made by his father, completing a mission from beyond the grave. Jonjo O'Neill's Jeffrey Meadows, calm and ruined, is the most unsettling villain the show had produced, and the episode's last note — Frost and Mullett standing together against the inspector — is as close to a happy ending as Denton gets.

A two-parter that ends with its killer choosing the bridge over the cell, and its hero and his superintendent standing together against the inspector. As close to a happy ending as Denton gets. As close to a happy ending as Denton gets.